Germany, the bloc's biggest economy and energy market, goes to the polls later this month and afterwards must reform its energy laws reflecting a costly low-carbon approach coupled with scepticism about fossil fuel production, including fracking.
"I advise you to keep all [gas fracking] options open ... that make [Russian leader Vladimir] Putin nervous," he said.
Oettinger, a German national, was alluding to unresolved differences in European fracking laws which leave shale gas output dormant despite its potential, while gas imports are rising, with Russia remaining the biggest single supplier.
Due to environmental concerns, Berlin has suspended plans to regulate hydraulic fracking until after September's election, prolonging the uncertainty that curbs its development.
Fracking, which involves pumping water and chemicals at high pressure thousands of metres below the ground to release gas, has helped lower energy prices in the United States, fuelling an industrial revival.
Oettinger said German industry could afford to pay 50% or 100% more for energy than rivals in the United States, "but not more than that".
Oettinger defended exemptions that Germany grants its industry from energy-related costs. They have come into the focus of an EU probe as neighbours and private German consumer groups complained about alleged distortions to competition.
"If industry wants to survive, it needs [energy cost] exemptions," Oettinger said. He called German Green Party ideas for further industry regulation "adventurous" and warned that industrial players could leave Europe to relocate elsewhere.
Turning to current EU climate policies, Oettinger warned that the bloc risked investing in too many ideas and research while it only accounts for a small part of global emissions.
The European Commission is due to propose 2030 climate protection goals later this year. Oettinger advised caution.
"It is becoming increasingly questionable whether our pioneering activities can be financed when the rest of the world does not follow suit," he said.